2014-12-16 00:42:20

by Dmitry Torokhov

Subject: [PATCH] PM / OPP: add some lockdep annotations

Certain OPP APIs need to be called under RCU lock; let's add a few
rcu_lockdep_assert() calls to warn about potential misuse.

Signed-off-by: Dmitry Torokhov <[email protected]>
---
drivers/base/power/opp.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index d24dd614a..852eebf 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -218,6 +218,11 @@ int dev_pm_opp_get_opp_count(struct device *dev)
struct dev_pm_opp *temp_opp;
int count = 0;

+ rcu_lockdep_assert(rcu_read_lock_held() ||
+ lockdep_is_held(&dev_opp_list_lock),
+ "dev_pm_opp_get_opp_count() needs rcu_read_lock() "
+ "or dev_opp_list_lock protection");
+
dev_opp = find_device_opp(dev);
if (IS_ERR(dev_opp)) {
int r = PTR_ERR(dev_opp);
@@ -267,6 +272,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
struct device_opp *dev_opp;
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);

+ rcu_lockdep_assert(rcu_read_lock_held() ||
+ lockdep_is_held(&dev_opp_list_lock),
+ "dev_pm_opp_find_freq_exact() needs rcu_read_lock() "
+ "or dev_opp_list_lock protection");
+
dev_opp = find_device_opp(dev);
if (IS_ERR(dev_opp)) {
int r = PTR_ERR(dev_opp);
@@ -313,6 +323,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
struct device_opp *dev_opp;
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);

+ rcu_lockdep_assert(rcu_read_lock_held() ||
+ lockdep_is_held(&dev_opp_list_lock),
+ "dev_pm_opp_find_freq_ceil() needs rcu_read_lock() "
+ "or dev_opp_list_lock protection");
+
if (!dev || !freq) {
dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
return ERR_PTR(-EINVAL);
@@ -361,6 +376,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
struct device_opp *dev_opp;
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);

+ rcu_lockdep_assert(rcu_read_lock_held() ||
+ lockdep_is_held(&dev_opp_list_lock),
+ "dev_pm_opp_find_freq_floor() needs rcu_read_lock() "
+ "or dev_opp_list_lock protection");
+
if (!dev || !freq) {
dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
return ERR_PTR(-EINVAL);
--
2.2.0.rc0.207.ga3a616c


--
Dmitry

2014-12-16 05:31:14

by Viresh Kumar

Subject: Re: [PATCH] PM / OPP: add some lockdep annotations

On 16 December 2014 at 06:12, Dmitry Torokhov <[email protected]> wrote:
> Certain OPP APIs need to be called under RCU lock; let's add a few
> rcu_lockdep_assert() calls to warn about potential misuse.

Very nice..

> Signed-off-by: Dmitry Torokhov <[email protected]>
> ---
> drivers/base/power/opp.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
> index d24dd614a..852eebf 100644
> --- a/drivers/base/power/opp.c
> +++ b/drivers/base/power/opp.c
> @@ -218,6 +218,11 @@ int dev_pm_opp_get_opp_count(struct device *dev)
> struct dev_pm_opp *temp_opp;
> int count = 0;
>
> + rcu_lockdep_assert(rcu_read_lock_held() ||
> + lockdep_is_held(&dev_opp_list_lock),
> + "dev_pm_opp_get_opp_count() needs rcu_read_lock() "
> + "or dev_opp_list_lock protection");
> +
> dev_opp = find_device_opp(dev);
> if (IS_ERR(dev_opp)) {
> int r = PTR_ERR(dev_opp);
> @@ -267,6 +272,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
> struct device_opp *dev_opp;
> struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
>
> + rcu_lockdep_assert(rcu_read_lock_held() ||
> + lockdep_is_held(&dev_opp_list_lock),
> + "dev_pm_opp_find_freq_exact() needs rcu_read_lock() "
> + "or dev_opp_list_lock protection");
> +
> dev_opp = find_device_opp(dev);
> if (IS_ERR(dev_opp)) {
> int r = PTR_ERR(dev_opp);
> @@ -313,6 +323,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
> struct device_opp *dev_opp;
> struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
>
> + rcu_lockdep_assert(rcu_read_lock_held() ||
> + lockdep_is_held(&dev_opp_list_lock),
> + "dev_pm_opp_find_freq_ceil() needs rcu_read_lock() "
> + "or dev_opp_list_lock protection");
> +
> if (!dev || !freq) {
> dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
> return ERR_PTR(-EINVAL);
> @@ -361,6 +376,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
> struct device_opp *dev_opp;
> struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
>
> + rcu_lockdep_assert(rcu_read_lock_held() ||
> + lockdep_is_held(&dev_opp_list_lock),
> + "dev_pm_opp_find_freq_floor() needs rcu_read_lock() "
> + "or dev_opp_list_lock protection");
> +

To get rid of the redundancy a bit, what about something like:

#define opp_rcu_lockdep_assert() \
rcu_lockdep_assert(rcu_read_lock_held() || \
lockdep_is_held(&dev_opp_list_lock), \
"Missing rcu_read_lock() or
dev_opp_list_lock protection");